The Brazilian government's National Indian Foundation (Funai) recently said it would conduct flyovers in Amazonia, where it suspects Indians might be in danger from encroaching farmers, loggers and miners.
Military planes flying at high altitude will use radar, satellite, and infrared technology that can identify humans and their communities through their body heat, Funai and military officials said.
If pilot programs scheduled for next year are successful, the high-tech equipment could prove an indispensable weapon in protecting vulnerable tribes.
"This is one of the tools to help us find and confirm the existence of isolated Indians," says Antenor Vaz, coordinator of the isolated Indians division at Funai and an experienced Amazonian explorer. "It will let us know where they are and what kind of environment they are in. We can determine if they are in danger; if there are ranchers or miners close to them."
The heat-sensitive technology will be on three planes that can fly at altitudes up to 36,000 feet, says Wougran Galvão, the product director at Sipam, the government's Amazonian monitoring agency. Such technology has already been used successfully in conjunction with satellite and radar imagery. But the upcoming tests will mark the first time it has been tapped to find humans.
"We have used this for lots of things before, along coastline, for intelligence work, to detect [illegal] charcoal factories, to see deforestation," Mr. Galvão says.
Mr. Vaz said the first tests should take place in the northwestern corner of Mato Grosso state, which is located in the western part of Brazil, which is on the southern edge of the Amazon rain forest. Concern is growing there over the future of the Piripkura tribe. The state, whose name means Thick Forest, has been largely denuded by loggers and farmers, and the areas that are still intact are now under threat.
The Piripkura live in one of those areas, a notoriously violent municipality called Coloniza, where illegal logging is endemic.
Funai's director classed the Piripkura's situation as "an emergency," and Survival International, a British-based indigenous rights group, called for prompt action to protect them.
The tribe may have as little as three members left, and encroaching loggers are deliberately trying to block their traditional paths in order to force them from their land, said Survival International's director, Stephen Corry.
"The Piripkura's land must be signed into law and protected immediately, otherwise they will be wiped out," Mr. Corry says.
Vaz said the overflights to identify the Piripkura would hopefully be the first of many. As the destruction of the Amazon has gathered pace, more remote tribes are seeing their traditional areas go up in smoke.
Today, 18 percent of the Amazon has disappeared, and Vaz said there are traces or reports of 39 uncontacted tribes. But while the new technology will help them verify those reports the intention is only to record their whereabouts, not make contact, he stressed.
That is thanks to a policy introduced in the 1980s by Vaz's predecessor, Sydney Possuelo.
Mr. Possuelo, an explorer who has discovered more Brazilian tribes than any other man alive, realized too many Indians were succumbing to diseases and alcoholism, right after being integrated into modern society.
Possuelo reversed that assimilation policy. Now, authorities make contact with remote tribes only if their existence is under threat.
"The philosophy that I implanted was one of not making contact," Possuelo says. "The more you penetrate into the forest, the more problems you give the Indians. We need to find them to protect them, so if you can detect them without going overland, you make it easier."
Although Possuelo expresses optimism that the new technology can help, he stresses that flyovers were just a start. Once contact has been confirmed, overland expeditions will be required to map out the area where the Indians live. Only then can authorities create and monitor reservations, he says.
"If they can check where these people are, it would be fantastic, but it does not eliminate the expeditions," Possuelo says. "You need to go in overland with teams to verify the extension of their area. You need to check that out on the ground and then you can delineate where they live."
Vaz agrees, and says he hopes the flyovers could become an integral part of keeping the Indians isolated and protected.
"When we first started this we had a rucksack on our backs, sometimes a map, if it existed, and guides to help us cut down trees," he says.
"As time has gone on, we got better maps, images from planes, then satellite images, then GPS [global positioning system]. Now we can go into the jungle with computers and communicate with the outside world. If we don't use this technology to protect the Indians, then they [farmers] will use it to go in and plant soy. In fact, they already are. We're late to this."